Alveolar targeting of aerosol pentamidine. Toward a rational delivery system

Nebulizer systems that deposit a high proportion of aerosolized pentamidine on large airways are likely to be associated with marked adverse side effects, which may lead to premature cessation of treatment. We have measured alveolar deposition and large airway-related side effects (e.g., cough, breathlessness, and effect on pulmonary function) after aerosolization of 150 mg pentamidine isethionate labeled with 99mTc-Sn-colloid. Nine patients with AIDS were studied using three nebulizer systems producing different droplet size profiles: the Acorn System 22, Respirgard II, and Respirgard II with the inspiratory baffle removed. Alveolar deposition was greatest and side effects least with the nebulizer producing the smallest droplet size profile (Respirgard II), whereas large airway-related side effects were prominent and alveolar deposition lowest with the nebulizer producing the largest droplet size (Acorn System 22). Values for alveolar deposition and adverse airway effects were intermediate using the Respirgard with inspiratory baffle removed, thus indicating the importance of the baffle valve in determining droplet size. Addition of a similar baffle valve to the Acorn System 22 produced a marked improvement in droplet size profile. Selection of a nebulizer that produces an optimal droplet size range offers the advantage of enhancing alveolar targeting of aerosolized pentamidine while reducing large airway-related side effects.

Pressurised aerosol deposition in the human lung with and without an "open" spacer device

A radiotracer technique has been used to assess aerosol delivery from a pressurised metered dose inhaler, used both with and without a 10 cm cylindrical spacer attachment (Syncroner), which has an open section in its upper surface. The radionuclide technetium-99m (99mTc) was added to sodium cromoglycate in a canister (Intal inhaler; 1 mg/puff); in vitro studies with a multistage liquid impinger showed that the radiolabel acted as a marker for the presence of drug over a wide range of particle sizes. Ten healthy volunteers were studied after they had inhaled from (1) a metered dose inhaler alone (slow inhaled flow rate, about 25 l/min); (2) metered dose inhaler plus spacer (slow flow rate); and (3) metered dose inhaler plus spacer (fast inhaled flow rate, about 100 l/min). Inhalation was coordinated with firing the spray and was followed by 10 seconds' breath holding. With the metered dose inhaler alone a mean 11.0% (SEM 1.4%) of the dose reached the lungs, compared with significantly higher doses for slow (16.1% (2.2%] and fast (13.3% (1.7%] inhalations through the spacer. The distribution pattern within the lungs was significantly more peripheral after slow inhalation. Oropharyngeal deposition was halved by the spacer. The open spacer should teach patients good coordination and delivers more aerosol to the lungs than a correctly used metered dose inhaler.

Delivery of albuterol and ipratropium bromide from two nebulizer systems in chronic stable asthma. Efficacy and pulmonary deposition

Bronchodilator responses to both nebulized albuterol (salbutamol) and ipratropium bromide and aerosol delivery to the tracheobronchial tree have been assessed in eight patients with chronic stable asthma (mean baseline FEV1, 50 percent; reversibility greater than 20 percent). Two commercially available nebulizer systems were used, namely, a Turret nebulizer operated at a compressed gas flow rate of 12 L/min (droplet MMD, 3.3 mu) and an Inspiron nebulizer driven at 6 L/min (MMD, 7.7 mu). Albuterol was given as doses of 250 micrograms, 250 micrograms, 500 micrograms, and 1,000 micrograms (cumulative dose, 2 mg) and ipratropium bromide as doses of 50 micrograms, 50 micrograms, 100 micrograms, and 200 micrograms (cumulative dose, 400 micrograms) at intervals of 35 minutes. For albuterol, bronchodilatation was significantly (p less than 0.05) greater at all dosage levels with the Turret. For ipratropium, bronchodilatation was similar for both nebulizers. Measurements of aerosol deposition using 99mTc-labelled pentetic acid (diethylenetriamine pentaacetic acid; DTPA) showed that 9.1 +/- 1.1 percent and 2.7 +/- 0.2 percent of the dose reached the lungs during nebulization to dryness for Turret and Inspiron, respectively (p less than 0.01); distribution within the lungs was similar for the two aerosols. Selection of nebulizer apparatus can influence delivery of aerosol and subsequent bronchodilator response to albuterol in patients with chronic stable asthma but is less important for aerosol delivery of ipratropium bromide in these patients.

The origins of depressed mood in rheumatoid arthritis

Most studies that have considered depressed mood in patients with rheumatoid arthritis have failed to analyze the relative contribution of psychological, social and disease state variables. Using multivariate statistical analyses we identified the role played by demographic, disease related, disability and social variables. Together these variables accounted for 44% of the variation in depressed mood. Demographic factors, disability measures, disease duration, social isolation and economic deprivation all made significant contributions to the explanation of depressed mood. The results of our study underline the importance of examining a wide range of factors in order to consider their relative influence on psychological state.

Subclinical neurological and neuropsychological effect of infection with HIV

Thirty one homosexual men with antibody to human immunodeficiency virus (HIV) but without major neurological complaints were assessed in a cross sectional study of neurological and neuropsychological function. Eleven patients had AIDS, 10 had persistent generalised lymphadenopathy (PGL), and 10 had HIV infection without PGL (called "well"). Thirteen age matched homosexual men without antibody to HIV acted as controls. Significant abnormalities were found in six on clinical neurological examination, in eight on nerve conduction studies, in six on electroencephalography, in six on neuropsychological assessment, and in eight on computed tomography of the head. Eighteen patients (nine with AIDS, four with PGL, and five "well") performed abnormally in at least one section of the assessment. The study highlights the incidence of nervous system dysfunction in HIV infection even in people who do not have AIDS. Prospective evaluation using electrophysiological and imaging techniques is necessary to assess the natural history of such manifestations and the effect of antiviral treatment.

Experience with circulatory arrest and hypothermia to facilitate thoracic aortic surgery

A total of 12 patients underwent surgical repair for thoracic aortic dissections with a technique which included cardiopulmonary bypass, profound hypothermia, high-dose thiopentone and circulatory arrest. Seven of nine early postoperative survivors made a complete recovery on clinical criteria. There were three perioperative deaths and there was one late postoperative death from chronic renal disease. There were no deaths among those operated on electively. Neuropsychological testing may help to define the consequences of circulatory arrest on higher function.

Inhaled corticosteroids can modulate the immunopathogenesis of pulmonary sarcoidosis

We investigated the effect of inhaled corticosteroids on the phenotypes and functional capacity of macrophages obtained by bronchoalveolar lavage from patients with pulmonary sarcoidosis. The results were correlated with clinical status and therapeutic efficacy. Ten symptomatic sarcoid patients (previously untreated) with radiological parenchymal shadowing and abnormal pulmonary function received inhaled budesonide, 800 micrograms m twice daily via a Nebuhaler for 16 weeks. A placebo group included ten healthy volunteers and five sarcoid patients with similar features to the treated group. Drug distribution studies showed that 10% of the inhaled drug was deposited in the alveolar region. All ten treated sarcoid patients had symptomatic relief with no adverse effects. Three of these ten patients had significant resolution of their radiological shadowing. No significant difference in pulmonary function was observed. At the cellular level, a significant decrease in lavage lymphocytosis was seen after 16 weeks, during which time there was a concomitant change in the phenotype and functional characteristics of the alveolar macrophage population. No similar changes were observed in the placebo group. Our results suggest that inhaled budesonide can modulate the aberrant immunological reactions existent in the lung in pulmonary sarcoidosis, and produce concomitant symptomatic relief with no side effects. It is postulated that this effect may occur through action on the local alveolar macrophage population.

Inhaled corticosteroids can modulate the immunopathogenesis of pulmonary sarcoidosis

We investigated the effect of inhaled corticosteroids on the phenotypes and functional capacity of macrophages obtained by bronchoalveolar lavage from patients with pulmonary sarcoidosis. The results were correlated with clinical status and therapeutic efficacy. Ten symptomatic sarcoid patients (previously untreated) with radiological parenchymal shadowing and abnormal pulmonary function received inhaled budesonide, 800 micrograms m twice daily via a Nebuhaler for 16 weeks. A placebo group included ten healthy volunteers and five sarcoid patients with similar features to the treated group. Drug distribution studies showed that 10% of the inhaled drug was deposited in the alveolar region. All ten treated sarcoid patients had symptomatic relief with no adverse effects. Three of these ten patients had significant resolution of their radiological shadowing. No significant difference in pulmonary function was observed. At the cellular level, a significant decrease in lavage lymphocytosis was seen after 16 weeks, during which time there was a concomitant change in the phenotype and functional characteristics of the alveolar macrophage population. No similar changes were observed in the placebo group. Our results suggest that inhaled budesonide can modulate the aberrant immunological reactions existent in the lung in pulmonary sarcoidosis, and produce concomitant symptomatic relief with no side effects. It is postulated that this effect may occur through action on the local alveolar macrophage population.

Deposition and clinical efficacy of terbutaline sulphate from Turbuhaler, a new multi-dose powder inhaler

A radioaerosol technique has been developed in order to assess deposition patterns from a new metered dose powder inhaler (Turbuhaler, Astra Pharmaceuticals). The radionuclide Tc99m dissolved in chloroform was added to a spheronised formulation of micronised terbutaline sulphate and the chloroform was allowed to evaporate. Turbuhaler subsequently delivered 0.5 mg of treated drug per metered dose. In vitro tests with a multistage liquid impinger showed that the fractionation of the drug dose between different particle size bands was similar to the fractionation of radioactivity. In a group of ten asthmatic patients, a mean 14.2% (SEM 2.1) of the drug dose was deposited in the lungs, with 71.6% (3.0) of the dose in the oropharynx. Of the remainder, 13.7% (2.1) was deposited on the mouthpiece, and 0.5% (0.2) recovered from exhaled air. The radiolabel was present in both central and peripheral zones of the lungs. All patients bronchodilated; forced expiratory volume in one second (FEV1) increased from 1.40 (0.24) l to 1.77 (0.24) l (p less than 0.01) 20 min after inhalation. These results suggest that both the distribution of drug and the clinical effect of terbutaline sulphate delivered from Turbuhaler are similar to those from a pressurised metered dose inhaler (MDI).

Deposition and clinical efficacy of terbutaline sulphate from Turbuhaler, a new multi-dose powder inhaler

A radioaerosol technique has been developed in order to assess deposition patterns from a new metered dose powder inhaler (Turbuhaler, Astra Pharmaceuticals). The radionuclide Tc99m dissolved in chloroform was added to a spheronised formulation of micronised terbutaline sulphate and the chloroform was allowed to evaporate. Turbuhaler subsequently delivered 0.5 mg of treated drug per metered dose. In vitro tests with a multistage liquid impinger showed that the fractionation of the drug dose between different particle size bands was similar to the fractionation of radioactivity. In a group of ten asthmatic patients, a mean 14.2% (SEM 2.1) of the drug dose was deposited in the lungs, with 71.6% (3.0) of the dose in the oropharynx. Of the remainder, 13.7% (2.1) was deposited on the mouthpiece, and 0.5% (0.2) recovered from exhaled air. The radiolabel was present in both central and peripheral zones of the lungs. All patients bronchodilated; forced expiratory volume in one second (FEV1) increased from 1.40 (0.24) l to 1.77 (0.24) l (p less than 0.01) 20 min after inhalation. These results suggest that both the distribution of drug and the clinical effect of terbutaline sulphate delivered from Turbuhaler are similar to those from a pressurised metered dose inhaler (MDI).

Evidence of prednisolone induced mood change ('steroid euphoria') in patients with chronic obstructive airways disease

1. It is a clinical impression that some patients given oral corticosteroids develop a sense of wellbeing that is 'inappropriate' to improvements in physical health. This has been termed steroid 'euphoria', but unlike steroid-induced psychosis it has not been documented. 2. To test for the size and frequency of this phenomenon, 20 patients with severe chronic obstructive airways disease (mean FEV1 0.86 l) were given 30 mg of prednisolone for 14 days, after a period of placebo administration in a single-blind study. 3. Lung spirometry and arterial saturation during exercise were measured serially, together with established measures of mood state. 4. No changes in spirometry or arterial saturation during exercise were detected until 7 days of active therapy. 5. Mood state did not change during the placebo period, but small significant reductions in anxiety and depression were measured after 3 days of prednisolone and before any measurable improvement in lung function. Mood state did not then further improve, despite measurable improvements in lung spirometry. 6. This is evidence that prednisolone may produce a mild 'inappropriate' sense of wellbeing within a population receiving the drug, rather than as an occasional idiosyncratic response.

Bronchodilatory therapy with nebuhaler: how important is the delay between firing the dose and inhaling?

Metered dose inhalers are sometimes used in conjunction with NebuhalerR, a 750 ml holding chamber, but the permissible delay time between actuating the aerosol into Nebuhaler and commencing inhalation is unknown. We have compared in 10 asthmatic patients the bronchodilator responses following inhalations of terbutaline sulphate from Nebuhaler after delays of 1, 5 and 30 seconds and following placebo inhalation. Terbutaline sulphate was administered as 2 puffs, each of 250 micrograms, separated by approximately 15 minutes. After each delay time, terbutaline produced increases in forced expiratory volume in one second (FEV1), peak expiratory flow rate (PEFR) and maximum expiratory flow following exhalation of 75% of the forced vital capacity (V max25) significantly greater than those after placebo (P less than 0.01). Changes in PEFR did not vary significantly among the three delay times, but the increases in FEV1 and in V max25 were significantly reduced with 30 seconds' delay. It is concluded that the delay between actuation into Nebuhaler and commencing inhalation can be extended from 1 second to 5 seconds without significant loss of drug efficacy, and that further extension to 30 seconds causes only a small loss of bronchodilatation: hence the delay time is unlikely to be of major importance in clinical practice.

Deposition pattern of nasal sprays in man

The intranasal distribution from an aqueous pump spray has been assessed in 13 normal subjects, using insoluble Teflon particles labelled with 99Tcm which were intended to simulate a suspension of drug particles. Three different combinations of metered volume and spray cone angle were compared. The main deposition of particles was in the anterior, non-ciliated, part of the nose, but some particles also penetrated more posteriorly into the main nasal passages and were cleared subsequently to the nasopharynx. No particles were detected in the lungs. With a single puff of 100 microliters volume, 46.5 +/- 4.4 (mean +/- SEM)% of the spray was retained in the anterior part of the nose after 30 minutes, but this was increased to 57.1 +/- 4.5% (P less than 0.05) with two puffs of 50 microliters. The latter were deposited over a significantly (P less than 0.05) smaller area in the nasal cavity. There was a trend towards lower particle retention and a greater area of deposition when the spray cone angle was decreased from 60 degrees to 35 degrees. These results indicate that the drug particles released from nasal pump sprays are distributed both to ciliated and non-ciliated zones, and that the choice of metered volume and possibly spray cone angle may play a role in determining the amount which penetrates to the main nasal passages.

Deposition of carbenicillin aerosols in cystic fibrosis: effects of nebuliser system and breathing pattern

Antibiotic aerosol treatment is successful in treating Pseudomonas infection in some patients with cystic fibrosis, but the amount of drug reaching the lungs is unknown. The deposition patterns of carbenicillin aerosols delivered from two commercially available nebuliser systems (the Turret nebuliser plus Maxi compressor and the Inspiron nebuliser plus Traveller compressor) have been compared in six patients with cystic fibrosis during tidal breathing. The aerosol mass median diameters were 3.2 and 7.3 microns. In addition, the aerosol from the Turret-Maxi nebuliser system was inhaled by a combination of tidal and deep breathing. After two minutes' breathing via a mouthpiece the mean (SEM) deposition in the lungs was 15.60 (1.5) mg carbenicillin with the Turret nebuliser plus Maxi compressor, but only 6.54 (1.09) mg with the Inspiron nebuliser plus Traveller compressor; the distribution pattern within the lung was significantly more peripheral with the former nebuliser system. These differences may be ascribed partly to the smaller droplet size from the Turret system and partly to the higher nebulisation rate from the more powerful Maxi compressor. Tidal plus deep breathing produced a further small but non-significant increase in lung aerosol deposition. A seventh patient, who failed to complete the trial, had little aerosol deposited in his lungs because he inhaled through his nose. These results emphasise the importance of correct selection of nebuliser equipment for antibiotic aerosol treatment.

In vitro comparison of DeVilbiss jet and ultrasonic nebulizers

Output, droplet size (by laser instrument), and nebulization time have been compared in vitro for eight individual ultrasonic nebulizers (DeVilbiss Pulmosonic) and eight individual jet nebulizers (DeVilbiss 646), the latter operated by compressed air at flows of 6 and 12 L/min. A solution of hypertonic (7 percent) saline was nebulized. The ultrasonic nebulizer retained a higher "dead" volume of solution on completion of nebulization (p less than 0.05), but the increase in saline concentration was less marked than for the jet (p less than 0.01). The mass of NaCl released as aerosol was similar for the ultrasonic and for the jet at 6 L/min but was increased for the jet at 12 L/min (p less than 0.05). There was a fivefold interindividual variation in output for the ultrasonic. Droplet mass median diameters for the ultrasonic (mean 5.4 micron) were slightly lower than those for the jet at 6 L/min (mean 6.0 micron, p less than 0.05) but were higher than those for the jet at 12 L/min (mean 3.7 micron, p less than 0.01). The ultrasonic emitted virtually no droplets less than 2 micron diameter and may be unsuitable for applications requiring high yields of fine particles for delivery to the peripheral lung regions.

The flow-pressure characteristics of compressors used for inhalation therapy

Data are presented on the relationships between air flow rates and pressures generated by 15 brands of domiciliary compressor currently used in the United Kingdom to drive jet nebulisers. Since compressor brands vary widely in power, care must be taken in the selection of appropriate models for efficient respiratory therapy.

Deposition pattern from a nasal pump spray

The initial distribution and subsequent clearance of aerosol from a hand-operated nasal pump spray has been assessed from gamma camera scans in ten normal subjects, following labelling of placebo sprays with 99Tcm labelled Teflon particles (mean diameter 2 micron). Aerosol was concentrated chiefly in the anterior part of the nose, but the area of deposition varied between subjects. No particles reached the lungs. A mean 56% of the dose was retained at the initial site of deposition 30 minutes after administration, while the remaining 44% of the dose had cleared to the nasopharynx. The initial partitioning of nasal pump sprays between ciliated and non-ciliated zones is relevant both for effective topical therapy of the nasal cavity, and for possible systemic drug delivery by the intranasal route.

The separate effects of tar and nicotine on the cigarette smoking manoeuvre

The separate effects of tar and nicotine on the cigarette smoking manoeuvre were investigated. Each of ten asymptomatic habitual smokers smoked three different commercially available cigarettes in a randomised order. The brands were chosen such that two had the same tar yield (10 mg) and two had the same nicotine yield (1.4 mg). The volume of smoke inhaled into the lungs was measured by tracing the smoke with the inert gas 81Krm. Puffing indices were recorded using an electronic smoking analyser and flowhead/cigarette holder. There was no difference in the total volume of smoke puffed from each of the cigarette brands. With cigarettes of the same tar level, the total inhaled smoke volume was lower with the higher nicotine cigarette (P less than 0.05): by contrast, with cigarettes of the same nicotine level, the total inhaled smoke volume was lower with the lower tar cigarette (P less than 0.02). Tar and nicotine appear to exercise independent control over the volume of smoke inhaled.

Response and acclimatisation of symptomless smokers on changing to a low tar, low nicotine cigarette

Ten symptomless smokers were switched from their usual cigarette to a low tar, low nicotine test cigarette for two weeks to investigate their immediate response and subsequent acclimatisation to the test cigarette. The tar (T) and nicotine (N) yields of the test cigarettes were T = 3.8 mg, N = 0.6 mg; the median yields of the usual cigarettes were T = 16.4 mg, N = 1.4 mg. The subjects were monitored over a six week period comprising a control period (usual cigarette), a test period (test cigarette), and a return period (usual cigarette), each lasting two weeks. The inhaled smoke volume (smoke from the burning tip of the cigarette which is subsequently inhaled) was measured with a non-invasive radiotracer technique. Puffing indices were recorded using an electronic smoking analyser and flowhead cigarette holder. Measurements were made at the beginning of the control period, at the beginning and end of the test period, and at the end of the return period. Subjects kept records of their cigarette consumption during each of the three periods. Apart from a small change in puff duration, cigarettes were smoked in the same way during the control and return periods. Mean and total puff volumes increased with the low tar, low nicotine cigarette but did not change from the beginning to the end of the test period. There was no significant change between the control, test, and return periods for mean inhaled smoke volume, total inhaled smoke volume, or cigarette consumption. It is concluded that when smokers are switched to a low tar, low nicotine cigarette the puff volume increases but there is no change in the inhaled smoke volume or daily consumption.

Inhaled smoke volume and puff indices with cigarettes of different tar and nicotine levels

Ten asymptomatic smokers each smoked a low, low-to-middle and a middle tar cigarette with approximately the same tar-to-nicotine ratio, in a randomised order. The inhaled smoke volume was measured by tracing the smoke with the inert gas 81Krm. Puffing indices were recorded using an electronic smoking analyser and flowhead/cigarette holder. Throughout the study neither the mean inhaled smoke volume per puff nor the total inhaled smoke volume per cigarette changed significantly; however, the mean and total puff volumes were largest with the low tar cigarette and decreased with the higher tar brands. Puff volume was related to puff work (rs = 0.83, P less than 0.001) but was not related to puff resistance (rs = 0.10, P greater than 0.1). It is concluded that when switched between brands with the same tar-to-nicotine ratio, smokers increase their puff volumes with a lower tar cigarette but do not change the volume of smoke inhaled. Puff work and puff resistance were significantly correlated (rs = 0.45, P less than 0.02).